NMDA和非NMDA受体参与介导猫脊髓内脏作害性信息传递

AIM: To study the role of N-methyl-D-aspartic acid (NMDA) and non-NMDA receptors in processing nociceptive visceral information in the spinal cord. METHODS: The firing of spinal dorsal horn neurons to colorectal distension (3-15 kPa, 20 s) by inflation with air of latex balloon was recorded in 25 anesthetized cats. RESULTS: 1) According to the patterns of responses to colorectal distension, the neurons with increase and decrease in firing were classified as excitatory and inhibitory, respectively. The former consisted of 17 short-latency abrupt (SLA) neurons, 11 short-latency sustained (SLS) neurons, 9 long-latency (LL) neurons. The 15 inhibited (Inh) neurons were recorded. 2) Microelectrophoretic administration of NMDA, quisqualic acid (QA), and kainic acid (KA) activated 67.6%, 78.4%, and 59.5% of the colorectal distension-excited neurons tested. Also, 60%, 86.7%, and 53.3% of Inh neurons were activated by these 3 amino acids. 3) Colorectal distension-induced excitatory responses were reduced by 35% +/- 10% and 65% +/- 14% by a selective NMDA receptor antagonist d,l-2-amino-5-phosphonovalerate (APV) and a selective non-NMDA receptor antagonist 6,7-dinitro-quinoxaline-2,3-dione (DNQX), respectively. Such DNQX-induced inhibition was significantly more potent than that by APV (P < 0.05). Colorectal distension-induced inhibitory responses were partially relieved by 30%-50% in 3/7 Inh neurons by DNQX, but not APV. CONCLUSION: Both NMDA and non-NMDA receptors are involved in transmission and/or modulation of spinal visceral nociceptive information and non-NMDA receptors may play more important role than NMDA receptors.     

NMDA和非NMDA受体介导猫脊髓伤害性和非伤害性信息传递

用多管微电极离子电泳技术研究猫脊髓背角神经元活动。８０％的神经元被兴奋性氨基酸ＮＭＤＡ、使君子氨酸、卡因酸或ＤＬ－高磺丙氨酸（ＤＬＨ）激活。ＮＭＤＡ受体拮抗剂ＡＰＶ和氯受酮，非ＮＭＤＡ受体拮抗剂ＤＮＱＸ以及广谱拮抗剂４－羟基喹啉酸（Ｋｙｎ）均抑制神经元的伤害性反应。Ｋｙｎ抑制非伤害性反应大大强于氯胺酮。ＮＭＤＡ和非ＮＭＤＡ受体均参与介导脊髓伤害性反应，非伤害性信息主要由非ＮＭＤＡ受体介导。     

NMDA受体机制在动脉压力反射中的介导作用(英文)

目的:研究N-甲基-D-天门冬氨酸(NMDA)受体机制在动脉压力反射中的作用。方法:头端延髓腹外侧区(RVLM)前交感神经元(presympathetic neuron)与动脉压力反射相关,它们可被电刺激主动脉神经或升高动脉血压所抑制,其自发放电具有心性节律。根据这一特性,本研究用电生理学方法在17只雄性SD大鼠鉴定了27个假想的(putative)RVLM前交感神经元。以这些神经元对电刺激主动脉神经的反应为指标,观察在同侧孤束核(NTS)或尾端延髓腹外侧区(CVLM)微注射选择性NMDA受体拮抗剂CPP(0.1μL,50mmol/L)的作用。结果:在NTS微注射CPP可完全阻断或减弱电刺激主动脉神经引起的神经元抑制,但血压升高引起的神经元抑制不能完全被消除,神经元放电的心性节律仍然存在;在CVLM,CPP不仅完全阻断电刺激主动脉神经引起的神经元抑制,而且阻断血压升高引起的神经元抑制,神经元放电的心性节律消失。结论:NMDA受体机制在动脉压力反射中起着重要的介导作用;单侧孤束核的压力敏感神经元向单侧RVLM投射。     

海马内非NMDA及GABA-A受体在青霉素致痫及电针抗痫中的作用

研究６，７ｄｉｎｉｔｒｏｑｕｉｎｏｘａｌｉｎｅ２，３ｄｉｏｎｅ（ＤＮＱＸ）和荷包牡丹碱（Ｂｉｃ）在青霉素致痫及电针抗痫中的作用．方法：Ｗｉｓｔａｒ大鼠（ｎ＝５３）海马内微量注入青霉素１μＬ（０２４μｇ），以脑电记录及其功率谱分析作为癫痫发作的指标．结果：电针和ｎｏｎＮｍｅｔｈｙｌＤａｓｐａｒｔａｔｅ（非ＮＭＤＡ）受体竞争性拮抗剂ＤＮＱＸ能部分抑制癫痫发作，电针和ＤＮＱＸ１μｇ合用时能加强对癫痫的抑制；而Ｂｉｃ可使电针对癫痫的抑制减弱．结论：海马内ＧＡＢＡＡ受体拮抗剂能部分翻转电针的抗痫作用，而电针和非ＮＭＤＡ受体拮抗剂有协同抗痫作用．     

脑缺血再灌注后NMDA受体亚基2B酪氨酸磷酸化的调节机制(英文)

目的:研究沙土鼠脑缺血再灌注后海马突触体N-甲基-D-天冬氨酸(NMDA)受体亚基2B(NR2B)酪氨酸磷酸化调节的机制。方法:沙土鼠双侧颈总动脉结扎形成前脑缺血模型;NR2B酪氨酸磷酸化通过免疫沉淀和免疫印渍分析。结果:脑缺血15分钟导致蛋白酪氨酸磷酸化水平明显下降;再灌注引起包括180kDa蛋白在内的多种蛋白酪氨酸磷酸化水平快速(再灌注15分钟)、持续(至少48小时)升高。免疫沉淀和免疫印渍证实,180 kDa条带为NR2B。缺血15分钟,再灌注6小时,NR2B酪氨酸磷酸化明显高于对照组,为对照组的1.8倍,而NR2B蛋白表达量则无变化。缺血前腹腔注射非竞争性NR拮抗剂氯胺酮或L-型电压门控钙通道(L-type VGCC)阻滞药硝苯地平,对NR2B酪氨酸磷酸化水平升高有明显的拮抗作用,而对NR2B蛋白表达量均无影响。在此条件下,非NMDA受体拮抗剂6,7-二硝基喹恶啉土卫四(DNQX)对NR2B酪氨酸磷酸化水平无影响。酪氨酸蛋白磷酸酶(PTP)抑制剂钒酸钠使脑缺血再灌注诱导的NR2B酪氨酸磷酸化进一步增加,而酪氨酸蛋白激酶(PTK)抑制剂金雀异黄素则使其减少。Src能与NR2B免疫共沉淀。结论:沙土鼠脑缺血再灌注NR2B的酪氨酸磷酸化的升高是通过NR和L-type VGCC介导的;PTK和PTP参与脑缺血再灌注NR2B酪氨酸磷酸化的调节,与NR2B以物理方式结合的Src可能在这种     

NO介导吗啡戒断大鼠脊髓Fos蛋白和NMDA_(1A)受体mRNA表达的增加

目的:观察NO在纳洛酮催促吗啡戒断大鼠脊髓神经元活动变化中的作用。方法:采用Fos免疫组织化学、NADPH-d组织化学、Fos/NADPH-d双标、鞘内注射、反义寡核苷酸和RT-RCR技术。结果:急性应用纳洛酮和慢性应用吗啡对大鼠脊髓Fos蛋白及NADPH-d阳性神经元表达无明显影响,二者也无Fos/NADPH-d双标神经元表达;纳洛酮催促吗啡戒断大鼠脊髓Fos蛋白、NADPH-d阳性神经元、纤维和终末表达明显增加,且出现Fos/NADPH-d双标神经元表达。预先鞘内注射nNOS反义寡核苷酸明显降低吗啡戒断症状评分,减少吗啡戒断大鼠脊髓Fos蛋白及NMDA_(1A)R mRNA表达。结论:NO介导吗啡戒断大鼠脊髓Fos和NMD_(1A)R mRNA表达的增加。     

谷氨酸树突处局部给药所引起的前额皮层锥体细胞爆发式放电:NMDA和非NMDA受体的作用(英文)

AIM: To investigate whether in the prefrontal cortical(PFC) pyramidal eells, focal glutamate application tothe apical dendrite induces bursting and whether theeffect of glutamate involves activation of both NMDAand non-NMDA receptors. METHODS: Pyramidalcells in layers Ⅴ and Ⅵ of the PFC were visualized inrat brain slices using infrared videomicroscopy andrecorded with whole-cell electrodes. Glutamate and itsagonists were focally applied to the apical dendrite andthe soma using microiontophoresis. RESULTS:Dendritic glutamate application (0--20 nA, 10 mmol/L) induced repetitive bursts in most cells tested (12/     

多巴胺和谷氨酸在纹状体脑片的相互作用:受体机制介导的CCDPKⅡ,PKA和LDH活性变化(英文)

目的:研究DA和Glu及其受体激动剂/拮抗剂对大鼠纹状体脑片Ca~(2 )/CaM依赖性蛋白激酶Ⅱ(CCDPKⅡ)、cAMP依赖性蛋白激酶(PKA)活性及乳酸脱氢酶(LDH)释放的影响,以探讨纹状体DA和Glu两个神经递质系统的相互作用。方法:用~(32)P掺入法测定大鼠纹状体脑片CCDPKⅡ和PKA活性,用比色法测定LDH的释放。结果:(1)NMDA受体拮抗剂MK-801能拮抗DA、D_1激动剂SKF 38393和D_2激动剂LY 171555对CCDPKⅡ活性的抑制作用。D_1拮抗剂SCH 23390和D_2拮抗剂spiperone均能拮抗Glu诱导的CCDPKⅡ活性降低。(2)DA和SKF 38393显著增加纹状体脑片PKA活性,MK-801可降低这种作用。(3)DA和Glu增加LDH的释放并与浓度成正比。MK-801拮抗DA诱导的LDH释放增加;spiperone能显著减少Glu诱导的纹状体神经元LDH释放。结论:DA和Glu的相互作用对调节纹状体神经元CCDPKⅡ和PKA活性及细胞功能是非常重要的。     

Involvement of GABA and opioid peptide receptors in sevoflurane-induced antinociception in rat spinal cord

AIM: The spinal cord is pivotal in immobility induced by volatile anesthetics because the anesthetics depress the activity of motor neurons in the spinal cord. The aim of this study was to observe the effects of sevoflurane on pain processing at the spinal level. METHODS: The firing of the gastrocnemius muscle was evoked by electrical stimulation to the ipsilateral hindpaw in rats. The nociceptive C response of electromyography (EMG) was selected to study. The GABAA receptor antagonist bicuculline (0.1 mg/kg) and opioid receptor antagonist naloxone (0.4 mg/kg) were administered intravenously, either in the presence or in the absence of 1.0% sevoflurane. RESULTS: In rats with transected spinal cord, sevoflurane produced a profound reduction in the C response in a dose- and time-dependent manner. In the presence of 1.0% sevoflurane, the C responses were increased after injections of bicuculline and naloxone. CONCLUSION: Sevoflurane is a volatile anesthetic that acts directly on the spinal cord to suppress the nociceptive reflex. The sevoflurane-induced suppression of the C response is antagonized by either bicuculline or naloxone. The results suggest that spinal GABAA receptors and opioid peptide receptors are involved in the sevoflurane-induced suppression of spinal nociception.     

Central benzodiazepine receptors in the spinal cord and other regions of the CNS of the cat

Central benzodiazepine (BZ) receptors were looked for in the spinal cord, cerebral cortex and cerebellum of the cat. Both [3H]Ro 15-1788 and [3H]flunitrazepam bound to benzodiazepine receptors with apparent dissociation constants (KD) in the nanomolar range and Hill coefficients near unity. The concentration of binding sites was much greater (10-40 times,depending on the ligand used) in the cortex and cerebellum than in the spinal cord. gamma-Aminobutyric acid (GABA) significantly reduced the KD value of the binding of tritiated flunitrazepam in all three areas of the central nervous system (CNS). The displacement of [3H]Ro 15-1788 by different benzodiazepine ligands indicates a relative prevalence of BZ1 (high affinity for beta-carboline esters and the triazolopyridazine, CL 218 872) in the cerebellum, a predominance of BZ2 (low affinity for the same agents) in the spinal cord and a mixture of both types in the cortex. The possibility that there is regional heterogeneity of receptors for benzodiazepines in CNS of the cat is discussed.     

脊髓5-HT_(2A)受体对大鼠慢性内脏痛敏反应及其电针治疗的影响

目的探讨脊髓5-羟色胺2A(5-HT2A)受体对大鼠慢性内脏痛敏反应及其电针治疗的影响。方法 SD大鼠分为正常对照组,慢性内脏痛模型组、模型加溶媒对照组、模型加酮色林组、模型加电针组、模型加针药合用组等6组。慢性内脏痛模型采用对新生幼鼠给予结直肠扩张刺激方法制备;电针选取双侧"足三里"和"上巨虚",疏密波,强度1 mA,持续30 min,隔日1次,持续4次。记录各组大鼠在结直肠扩张刺激诱导下腹壁撤退反射评分和腹外斜肌放电幅值。结果①在20和40mmHg压力刺激下,模型加酮色林组大鼠腹壁撤退反射评分高于模型组(P<0.05,P<0.01)和模型加针药合用组大鼠(P<0.05,P<0.01)。②在3种不同压力刺激下,模型加酮色林组大鼠腹外斜肌放电幅值皆高于模型组和模型加针药合用组大鼠(P<0.05)。结论脊髓5-HT2A受体能够降低慢性内脏痛大鼠的痛觉敏化,但在电针治疗慢性内脏痛敏反应中可能不起主要作用。     

腺苷A1受体和NMDA受体在海马齿状回突触传递活动中的关系

目的　探讨腺苷A1受体阻断剂对海马齿状回 (DG)突触传递活动的影响及其与NMDA受体的关系。方法采用在体记录麻醉大鼠LTP的电生理学方法 ,观察腺苷A1受体特异性阻断剂 8 环戊 1,3 二丙基黄嘌呤 (DPCPX)与NMDA受体激动剂、阻断剂在海马DG基础突触传递活动和高频刺激诱导的LTP中作用的相关性。结果　DPCPX(6mg·L- 1,5μL ,icv)或NMDA(0 2mg·L- 1,5μL ,icv)不影响大鼠海马DG突触传递活动 ,DPCPX对icvNMDA后高频刺激诱导已形成的LTP维持也无影响 ;预先给予DPCPX后则可显著增强NMDA的海马DG基础突触传递活动和LTP ;AP5(0 5mg·L- 1,5μL)阻断NMDA受体后对LTP的抑制作用不受DPCPX的影响 ,但预先给予DPCPX则可取消AP5 对LTP的抑制作用。结论　DPCPX不影响海马DG突触传递活动 ,但可影响NMDA受体的效应 ,增强NMDA受体在海马DG突触传递活动中的作用     

Guibourtia tessmannii-induced fictive ejaculation in spinal male rat: involvement of D1, D2-like receptors

Context: Guibourtia tessmannii (Caesalpiniaceae) is a plant traditionally used as aphrodisiac. We previously reported the pro-ejaculatory effects of the aqueous and methanol extracts of G. tesmannii in spinal male rat. However, the mechanism underlying such effects has not been elucidated.

Objective: This study characterizes the dopaminergic sub-type receptors involved in G. tesmannii-induced ejaculation in male Wistar rat.

Materials and methods: Urethane-anesthetized spinal male rats were intravenously treated with saline solution (1?mL/kg, control); dopamine (0.1?μmol/kg, reference); aqueous or methanol extracts of G. tesmannii (20?mg/kg) in the absence or presence of haloperidol (0.26?μmol/kg), a nonspecific dopaminergic receptor antagonist, Sch23390 (0.26?μmol/kg), a specific D1-like receptor antagonist or, sulpiride (0.26?μmol/kg), a specific D2-like receptor antagonist. Electromyography of the bulbospongiosus muscles and intraseminal pressure were recorded after urethral, penile and drug stimulations.

Results: Urethral and penile stimulations, intravenous injection of dopamine or, aqueous and methanol extracts of G. tesmannii always triggered the expression of rhythmic contraction of the bulbospongiosus muscles with an average mean of 3.33?±?0.43; 7.83?±?0.85; 9.80?±?0.86; 0.83?±?0.54 and 2.67?±?0.95 contractions, respectively. The intraseminal pressure was more expressed after urethral and penile stimulations (15.66?±?1.58 and 13.60?±?2.40?mmHg, respectively). In rats pretreated with haloperidol, Sch23390 or sulpiride, no ejaculation was recorded after intravenous injection of G. tesmannii extracts or dopamine.

Discussion and conclusion: Guibourtia tesmannii-induced ejaculation requires the integrity of D₁ and D₂-like receptors. These findings further justify the ethno-medicinal claims of G. tesmannii as an aphrodisiac.     

辣椒素受体参与骶髓后联合核神经元突触传递

目的研究辣椒素受体对大鼠骶髓后联合核(SDCN)神经元突触传递的影响。方法在脊髓骶段横切薄片上,利用全细胞膜片钳法记录骶髓后联合核神经元谷氨酸能兴奋性突触后电流(EPSCs)和γ-氨基丁酸(GABA)能抑制性突触后电流(IPSCs),比较激动辣椒素受体后上述突触电流的变化;观察激动辣椒素受体对SDCN神经元动作电位发放的影响。结果辣椒素受体被其特异性激动剂辣椒素(1μmol.L-1)激动后,自发EPSCs(sEPSCs)的频率和振幅均有明显增加(P<0.05,n=17)。在河豚毒素(0.5μmol.L-1)存在的条件下,辣椒素明显增加微小EPSCs(mEPSCs)的频率(P<0.01,n=13),但对mEPSCs的振幅无影响(P>0.05,n=13),提示辣椒素的作用在突触前。辣椒素也明显增加动作电位发放(P<0.05,n=19)。上述作用均可被辣椒素受体特异性拮抗剂capsazepine(10μmol.L-1)阻断。辣椒素也增加GABA能的自发IPSCs(sIPSCs)的频率(P<0.05,n=20),但对其不依赖动作电位的微小IPSCs(mIPSCs)的频率或振幅均无作用(P>0.05,n=9)。结论在SDCN,辣椒素受体主要表达于兴奋性突触终末;激动辣椒素受体影响兴奋性和抑制性突触活动,并可能参与痛觉信息在脊髓水平的传递和调制。     

Role of peripheral and spinal 5-HT2B receptors in formalin-induced nociception

In this study we assessed the role of local peripheral and spinal serotonin 2B (5-HT_2B) receptors in rats submitted to the formalin test. For this, local peripheral ipsilateral, but not contralateral, administration of the highly selective 5-HT_2B receptor antagonist 2-amino-4-(4-fluoronaphth-1-yl)-6-isopropylpyridine (RS-127445, 0.01-1 nmol/paw) significantly prevented 1% formalin-induced flinching behavior. Moreover, local peripheral ipsilateral, but not contralateral, of the selective 5-HT₂ receptor agonist (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI, 1-10 nmol/paw) augmented 0.5% formalin-induced nociceptive behavior. The local pronociceptive effect of the 5-HT₂ receptor agonist DOI (10 nmol/paw) was significantly prevented by the local injection of RS-127445 (0.01 nmol/paw). Moreover, intrathecal injection of the selective 5-HT_2B receptor antagonist RS-127445 (0.1-10 nmol/rat) also prevented 1% formalin-induced nociceptive behavior. In contrast, spinal injection of the 5-HT₂ receptor agonist DOI (1-10 nmol/rat) significantly increased flinching behavior induced by 0.5% formalin. The spinal pronociceptive effect of the 5-HT₂ receptor agonist DOI (10 nmol/rat) was prevented by the intrathecal injection of the 5-HT_2B receptor antagonist RS-127445 (0.1 nmol/rat). Our results suggest that the 5-HT_2B receptors play a pronociceptive role in peripheral as well as spinal sites in the rat formalin test. 5-HT_2B receptors could be a target to develop analgesic drugs.     

大鼠尾状核内注射高剂量L-( )-2-氨基-3-磷酸基丙酸的神经毒性

目的:观察代谢型谷氨酸受体部分激动剂/拮抗剂L-( )-2-氨基-3-磷酸基丙酸(L-AP_3)脑内注射引起的神经毒性作用,并探讨其机制。方法:大鼠尾状核内微量注射药物后,观察动物意识状态和活动情况,测定脑组织含水量、Na~ 、K~ 、Ca~(2 )含量及血脑屏障(BBB)通透性变化,并进行组织学研究。结果:L-AP_3 600nmol脑内注射后动物出现嗜睡,并引起脑组织含水量、Na~ 和Ca~(2 )含量增加,K~ 含量减少,同时BBB通透性增加P<0.01,L-AP_3 60nmol未产生上述变化。电镜检查发现L-AP_3引起星形胶质细胞高度肿胀,神经元变性坏死。D-( )-2-氨基-3-磷酸基丙酸和L-( )2-氨基-4-磷酸丁酸不能模拟L-AP_3引起的变化,DL-2-氨基-5-磷酸基戊酸可以减轻L-AP_3的作用,(±)-α-甲基-(4-羧基苯基)甘氨酸不能减轻L-AP_3的作用。结论:脑内注射高剂量的L-AP_3引起神经毒性作用,以血管源性脑水肿、神经元损伤及脑组织高Ca~(2 )含量为特征,此作用是立体构型特异的,可能与磷脂酶C激活有关,部分通过NMDA受体介导。